For those who choose to install it, the inbox disappears from the main app ...

Direct is what Instagram calls its messaging feature which allows users to correspond with one another without publishing to the public. Direct also has four exclusive photo and video filters that are not now in the main Instagram app, including a amusing one that randomly bleeps your voice and covers up your mouth.

"We want Instagram to be a place for all of your moments, and private sharing with close friends is an important part of that", Instagram product manager Hemal Shah told The Verge.

Instagram believes that messaging experiences are best delivered via a stand-alone app instead of within a larger app, mostly echoing CEO Mark Zuckerberg's sentiments from a few years back that "there's a big premium on creating single-purpose, first-class experiences" in mobile.

The Verge reports that Direct is being tested on both iOS and Android in six countries: Chile, Israel, Italy, Portugal, Turkey, and Uruguay. You can take a photo or video with the front and rear cameras, apply face filters and masks, and even write text.

For Instagram parent Facebook, the test - first reported by The Verge - is part of a broader effort to dominate the messaging marketplace. Overall, when this app gets released, you should feel right at home with it if you've ever used Instagram Stories. Creators came up with it because they feel that it's hard to have a great private messaging experience in the same app that allows you to publicly broadcast messages.

An account and settings option will live to the camera's left, while swiping the other way will present you with the list of chats, exactly as it works on Instagram's main app now. It's a brand new app that connects to your Instagram profile and is strictly about direct messaging. It opens camera-first, so just like Snapchat, and it's very simple, with only three screens.

Further mirroring Snapchat, Facebook also began inviting Messenger users to add animated reactions, filters, masks and other effects to their video chats, earlier this year. Whether that happens later or not remains to be seen but it makes sense for it to be within the messaging app.